Much effort has been made toward the development of a wrought, Ni-base high-temperature alloy for turbine applications such as combustor liners, with limited success. For example Haynes alloy HR230® has a creep strength of 1000 hours at 1100° C., but its oxidation resistance is limited because it forms a chromia scale at high temperatures. Rapid formation of chromia leads to thick oxides which spall and cannot achieve the required lifetimes. Furthermore, chromia reacts with oxygen and water vapor above 600° C. to form a volatile reaction product (CrO2(OH)2 which increases the rate of degradation in most combustion environments. For example, the combustor liner on a small turbine needs to operate for 25,000-40,000 h at high temperature before the first major overhaul.
Moreover, Haynes alloy HR214® and Haynes alloy HR224® have oxidation resistance associate with the formation of alumina scales at temperatures up to 1100° and 1000° C., respectively. However, these alloys may not have sufficient phase stability or creep strength for some high temperature applications. Use of alumina- or chromia-forming Ni-base alloys requires trade-off in alloy properties. Other potential applications are concentrated solar power receivers and heat exchangers. Wrought alloys are desirable wherever sheet material is needed for applications such as combustor liners and associated hot gas paths in turbines and other high temperature applications. Heat exchanger applications could include primary surface recuperators and/or heat exchangers where the wall thickness may only be 50-250 μm. In this case, the alloy must possess both creep and oxidation resistance for applications that have operating temperatures in the range of 800° to at least 1100° C.